Bipedalism, speech, and intellect are the most prominent traits that emerged in the evolution of Homo sapiens. Here, we describe a novel genetic cause of an “involution” phenotype in four patients, who are characterized by quadrupedal locomotion, intellectual impairment, the absence of speech, small stature, and hirsutism, observed in a consanguineous Brazilian family. Using whole-genome sequencing analysis and homozygous genetic mapping, we identified genes bearing homozygous genetic variants and found a homozygous 36.2 kb deletion in the gene of glutamate receptor delta 2 (GRID2) in the patients, resulting in the lack of a coding region from the fifth to the seventh exons. The GRID2 gene is highly expressed in the cerebellum cortex from prenatal development to adulthood, specifically in Purkinje neurons. Deletion in this gene leads to the loss of the alpha chain in the extracellular amino-terminal protein domain (ATD), essential in protein folding and transport from the endoplasmic reticulum (ER) to the cell surface. Then, we studied the evolutionary trajectories of the GRID2 gene. There was no sign of strong selection of the highly conservative GRID2 gene in ancient hominids (Neanderthals and Denisovans) or modern humans; however, according to in silico tests using the Mfold tool, the GRID2 gene possibly gained human-specific mutations that increased the stability of GRID2 mRNA.

The Indochinese thick-thumbed bat, Glischropus bucephalus, was described in 2011, but its molecular genetics (and the genetics of the whole genus Glischropus) are still poorly studied. We defined and annotated the complete mitogenome of Glischropus bucephalus (Chiroptera: Vespertilionidae) from Vietnam. The complete mitogenome is 17,023 bp in total length, which includes 13 complete protein-coding genes, 22 tRNA genes, 2 rRNA, and one non-coding region (the origin of replication). The nucleotide composition is 33.2% A, 29.7% T, 13.6% G, and 23.5% C. The mitochondrial protein-coding genes use the standard start codon (ATN), one complete stop codon (TAA), and two incomplete stop codons (TA- and T-). The phylogenetic analysis confirmed that the genus Glischropus belongs to the Pipistrellini tribe and revealed that Glischropus bucephalus is clustered with the “eastern” clade of Pipistrellus, supporting the paraphyletic nature of the latter genus.

The northern three-toed jerboa Dipus sagitta had long been considered to be a single polytypic species. High genetic diversity of D. sagitta was earlier revealed on the basis of several mitochondrial and nuclear genes, and several separate species were hypothesized to occur within the taxon. However, the relationships between phylogenetic lineages have not been established because of the small sample size of nuclear genes. In the present work, a far larger set of nuclear DNA loci was used, and thus, a higher resolution of the phylogenetic tree was achieved for ten D. sagitta forms. The structure revealed for the species mainly confirmed the topology and relationships of the mtDNA lineages. Yet the mitochondrial and nuclear phylogenies were not completely consistent. Some of the D. sagitta genetic lineages were therefore assumed to be a product of reticular evolutionary processes. The taxon was concluded to be the diverse species complex D. sagitta sensu lato, in which long-diverged lineages are not always reproductively isolated.

A range-wide phylogenetic/phylogeographic study of the three-toed jerboas of the genus Stylodipus is conducted using the mitochondrial cytb gene and fragments of several nuclear genes. The genus has been believed to include three species: S. telum (W Central Asia, SE Europe), S. andrewsi (E Central Asia), and S. sungorus (Dzungar basin). Our data support the dichotomy between S. andrewsi and the other taxa forming S. telum species group. Within the latter, both mtDNA and nuclear loci indicate a species-level divergence between S. telum and the S. t. birulae lineage (Zaisan depression, NE Kazakhstan), previously considered a subspecies of S. telum and here elevated to full species. S. sungorus is recovered as a close sister group to S. birulae on the basis of nuclear data but clustered with S. telum in the mitochondrial tree. The latter taxon is the most variable and includes two closely related eastern and western sublineages, separated by the Volga-Ural sands and joined by a more divergent S. t. karelini lineage (E Kazakhstan). The observed mitonuclear discordance is hypothesized to occur due to mtDNA introgression resulting from hybridization between S. sungorus and S. t. karelini, which highlights the important role of reticulations in the evolution of Dipodidae.

The northern three-toed jerboa Dipus sagitta was long considered to be a single polytypic species. Earlier, a high genetic diversity of D. sagitta was revealed on the basis of several mitochondrial and nuclear genes, and the existence of several separate species within it was hypothesized. However, a small number of available nuclear genes prevented the establishment of relationships between identified phylogenetic lineages. Here, we significantly expand the set of utilized nuclear DNA loci, which resulted in a sufficiently higher resolution of the phylogenetic tree for 10 forms of D. sagitta. The identified species structure mainly confirms the topology and relationship of the mtDNA lineages. At the same time, the mitochondrial and nuclear phylogenies are not completely consistent. Hence, a part of the genetic lineages of D. sagitta is apparently a product of reticular evolutionary processes. This taxon is thus the diverse species complex D. sagitta sensu lato, in which long-diverged lineages are not always reproductively isolated.